WSJT-X/lib/encode232.f90

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Fortran
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subroutine encode232(dat,nsym,symbol)
! Convolutional encoder for a K=32, r=1/2 code.
integer*1 dat(13) !User data, packed 8 bits per byte
integer*1 symbol(206) !Channel symbols, one bit per byte
integer*1 i1
include 'conv232.f90'
nstate=0
k=0
do j=1,nsym
do i=7,0,-1
i1=dat(j)
i4=i1
if (i4.lt.0) i4=i4+256
nstate=ior(ishft(nstate,1),iand(ishft(i4,-i),1))
n=iand(nstate,npoly1)
n=ieor(n,ishft(n,-16))
k=k+1
symbol(k)=partab(iand(ieor(n,ishft(n,-8)),255))
n=iand(nstate,npoly2)
n=ieor(n,ishft(n,-16))
k=k+1
symbol(k)=partab(iand(ieor(n,ishft(n,-8)),255))
if(k.ge.nsym) go to 100
enddo
enddo
100 continue
return
end subroutine encode232